Certified Ophthalmic Assistant Practice Exam

If a patient is unable to distinguish the largest letter on a Snellen chart, the assistant should determine if the patient can count fingers at a given distance. This is because being unable to distinguish the largest letter indicates very poor visual acuity. By checking if the patient can count fingers at a certain distance, the assistant can evaluate the patient's ability to perceive larger objects at a closer range, providing a rough estimate of visual acuity in situations where the letter chart is not effective.

Options A, B, and D are not the correct next steps in this scenario. Proceeding to the next line on the Snellen chart may not be helpful if the patient is already unable to distinguish the largest letter. Checking for color blindness is not relevant to the situation of inability to distinguish the largest letter on the chart. Changing the chart is also not necessary as the issue lies with the patient's ability to perceive the letters rather than the chart itself.